Abstract: A satellite radio receiver obtains signals from a satellite receiving installation comprising one or more frequency converters which may, for example, undergo a frequency drift as a result of temperature variations which cannot be compensated for by an AFC circuit which is located in the satellite radio receiver and which controls a carrier oscillator for carrier regeneration in a demodulator circuit. A local oscillator for a mixer is designed as a PLL local oscillator (44) which can be tuned in large or small increments. The AFC circuit (1) and a synchronizing signal evaluation circuit (40) are coupled to a control circuit (34) so that the PLL local oscillator (44) is tuned: 1) outside the control range of the AFC circuit (1), with a large tuning increment in the case of undetected synchronizing signals, and 2) with a small tuning increment in the case of detected synchronizing signals, until the control range of the AFC circuit (1) is reached.
April 6, 1995
Date of Patent:
May 14, 1996
Deutsche Thomson-Brandt GmbH
Otto Klank, Klaus Eilts-Grimm, Jurgen Laabs
Abstract: Jitter of an overlay display with respect to the primary display of a television receiver is avoided by assuring that the vertical and horizontal blanking signal components are sufficiently time spaced by preventing the number of clock pulses occurring between the horizontal and vertical components of the blanking signal from going below a selected number. The number of clock pulses between the negative going transition of the vertical blanking signal and the positive going transition of the first horizontal blanking signal is tracked and when the number of pulses fails to exceed a reference value the number of pulses is changed to effectively shift the transitions with respect to one another.
Abstract: A radio receiver having switching-over to traffic announcement wherein the bass and treble frequency responses and the volume are changed to a value which is subjectively optimum for the respective actual driver and the announcement becomes more pleasant and easier to understand for him/her without the necessity for the driver to manually change the bass and treble controls. The switching-over of the bass and treble audio frequencies preferably occurs a short time before the switching-over of the announcement. Additionally, further switchings-over can be carried out which are advantageous for the attention of the driver. For example, switching off acoustically disturbing devices such as fans.
Abstract: A mixer for mixing first and second signals for providing a difference signal comprises a mixing transistor. The first and second signals are applied between the base and emitter electrodes of the transistor. A non-linear impedance is coupled in series with the emitter electrode. Spurious signal components are reduced in amplitude compared with the difference signal.
Abstract: An AC line signal of unknown frequency is compared to a signal of known reference to determine the frequency of the AC line signal. Thereafter, the AC line frequency signal is used as a time-base for keeping real time.
Abstract: The invention relates to a display system using a remote control handunit having "pointing function" capability for moving a cursor displayed on a display screen by changing the angular position of the remote control handunit. Specifically, the individual transmitting transducers of the remote control handunit are driven with signals having a predetermined phase relationship relative to each other such that the resultant phase received by the receiver is indicative of transmitter angular position.
Abstract: A digital input signal to be delayed is applied to a two-point linear interpolation filter which imparts delay to the signal proportional to the value of a delay control signal. Errors in both the amplitude and the phase of the delayed signal are minimized by the addition of a correction signal to the delayed signal. The correction signal is provided by applying the input signal to a further filter and a multiplier connected in cascade. The further filter is a linear phase filter having a response zero at zero frequency and a delay equal to an add multiple of one-half of the sampling period, Ts, of the digital input signal. The multiplier is controlled so as to vary the amplitude of the compensating signal as a non-linear function of the delay control signal so as to provide maximum amplitude compensation at delays corresponding to odd multiples of Ts/2 and zero amplitude compensation at delays equal to integer multiples of Ts.
Abstract: A data display video monitor includes an automatic kinescope bias (AKB) control system for the type wherein kinescope cathode output pulses representative of the black current level conducted by the kinescope are produced in response to energizing the kinescope grid during sensing intervals. As a result of this operation, plural horizontal lines along the top edge of the visible display screen area are illuminated. To reduce the visible effect of the illuminated lines, the AKB system is activated for short sensing intervals (e.g., two seconds or less) between considerably longer holding intervals (e.g., five minutes).
Abstract: A television receiver includes an audio signal processing arrangement for expanding a second audio program (SAP) signal compressed in accordance with the "dbx" system in a relatively simple manner. The signal processing arrangement includes a first filter for providing a first amount of deemphasis. A controllable gain amplifier has its input coupled to the filter and its gain controlled by a filtered signal representative of its input signal. A second filter at the amplifier output provides a second amount of deemphasis.
Abstract: An "Anti-Piracy" system and method are disclosed which includes an FSK modulator at the head end CATV transmitting location which, in response to data from an addressing computer, randomly issues Anti-Piracy commands (APC) which are transmitted to the set-top converters in the system. The converters are programmed to anticipate an interrupt in the FSK RF signals following the reception of an APC signal. The system and method are designed to curtail piracy by the use of audio recording techniques which have been used to obtain unauthorized service.
Abstract: A slow motion system includes a variable interlace constant line-rate video camera, a variable speed recorder and a line-rate converter connected in cascade. During slow motion shooting the camera interlace ratio is increased, the recorder playback speed is reduced by the interlace ratio and the converter increases the line-rate of the recorded signal in proportion to the interlace ratio thereby providing a constant field-rate constant line-rate video output signal having a temporal resolution which increases as the interlace ratio increases.
Abstract: A solid-state imager for a television camera which generates a compatible wide-screen signal, i.e., a wide-screen signal with compressed left and right edge portions for each television line. The solid-state imager includes photosensitive picture elements (pixels) which are nonuniformly distributed in each row of the imager in accordance with the amount of compression desired in the left and right edge portions of the signal.
Abstract: In a wideband video signal processing system, a video signal is capacitively coupled to a kinescope via a signal path. A video signal clamping diode is coupled from the video signal path to a low impedance point in a feedback path of a keyed switching transistor. Parasitic capacitances associated with the clamping diode and with the output of the switching transistor are decoupled from the video signal path by means of a first decoupling resistor, and a second decoupling resistor included in the feedback path, respectively.
Abstract: A speed-up memory doubles the field rate of a video input signal by repeating each field to reduce flicker when the double field rate signal is displayed. Read/write clocks for controlling the memory are locked to the color subcarrier of the video input signal thereby tending to produce visual artifacts in the displayed image due to clock skew relative to sync when non-standard video signals are processed. The skew errors are corrected by circuitry which measures the skew of the read and write clocks and delays the video signal as a function of a difference between the clock skew measurements.
July 31, 1985
Date of Patent:
July 14, 1987
Donald H. Willis, Russell T. Fling, Todd J. Christopher
Abstract: A progressive scan receiver includes a frame interpolation filter for generating added lines for display in a given field from a video input signal by interpolation from corresponding elements of immediately preceding and following fields. A second filter provides a line interpolated signal having picture elements spatially and temporally coincident with corresponding elements of the frame interpolated signal and having a suppressed vertical detail component. A third filter attenuates the vertical detail component of the frame interpolated signal. An output circuit combines the signals of the three filters to provide a frame interpolated video output signal in which the vertical resolution of the video input signal is preserved and motion artifacts characteristic of frame interpolation are attenuated.
Abstract: The line rate of a video input signal is doubled for display in progressive scan fashion by dual mode processor which generates added lines for the display by interpolation when displaying normal television pictures and by replication (repeating lines) when displaying characters. The processor mode is automatically controlled by an image analyzer which identifies fields of text by counting "major" transitions of the video input signal occurring within a field and comparing the count with a threshold value. Errors in identification are minimized by a further counter which integrates the field count and a hysteresis detector which controls the processor operating mode in accordance with high and low limits of the integrated field count.
Abstract: A CATV addressable converter is provided with a multi-purpose bi-directional data port for transmitting and/or receiving serial digital data. A micro-computer provided within the converter is programmed to make the converter responsive to RF commands transmitted over a television distribution system by an addressing computer or to the digital command signals received from an external device through the data port. The micro-computer coordinates the exchange of data between the converter and the external device to implement several converter functions. The data port provides a means by which an external device can read or alter data stored in the converter memory. This facilitates testing during and after manufacture as well as converter installation and address assignment procedures. The converter port can also be used to establish a communication link between two or more converters. The resulting hard-wire link between the converters prevents a form of piracy prevalent in the CATV industry.
Abstract: A television receiver includes apparatus for stabilizing an on-screen character display by which the deflection signal source is controlled for operating in a free-running mode, substantially unaffected by signal variations on the sync input line, rather than in a synchronized mode when sync is unreliable or otherwise undesirable. As another feature, the deflection signal source is caused to operate at substantially the same frequency in either mode.
May 10, 1985
Date of Patent:
June 30, 1987
Robert A. Pitsch, Billy W. Beyers, Jr., Larry G. Moore, Juri Tults